Laserfiche WebLink
Access Portal Collapse Repair and Equipment and Stope Rock Removal Work Plan March 2, 2012 <br />May Day No. 1 <br />2.0 WORK PLAN <br />The following presents a corrective action work plan to repair the Access Portal collapse, to <br />remove buried equipment from the Mill Portal, and to remove stope rock in accordance with <br />MSHA and DRMS regulatory requirements. Prior investigations were initiated to evaluate the <br />conditions that caused the portal collapse and an approach to repairing the collapse and the <br />removal of equipment and rock that exists on the floor of the adit and stope. <br />2.1 Prior Investigation <br />In August 2010, a principal geotechnical engineer, J. Erich Rauber visited the site to observe <br />and map the portal collapse and develop conclusions and recommendations regarding <br />repair /mitigation. Mr. Rauber is Wildcat's current geotechnical engineer of record. <br />Wildcat observed the collapse of the Mill Portal and the Access Portal. Preliminary observations <br />and mapping indicates the Mill Portal and a section of the Access Portal penetrated an old <br />landslide composed of colluvial materials. <br />The formerly dormant landslide was likely reactivated as a result of disturbance, and an <br />accompanying loss of shear strength caused by installation of the Mill Portal. A particularly wet <br />spring in 2009 further reduced the shear strength of the colluvium/landslide debris. <br />Approximately 2,300 cubic yards of collapsed debris were generated by the failure. <br />2.2 Phase 1 Scope of Work: Tasks 1- 4 <br />Initial work at the May Day No. 1 portal area will consist of installation of best management <br />practices (BMPs) for erosion and sedimentation control on the bench. This will consist of <br />installation of silt fence, straw wattles and/or straw bales along the outside, down - gradient edge <br />of the bench. This erosion control will parallel the outer edges of the May Day No. 1 bench <br />approximately 240 feet down - gradient of the work areas. The locations of BMPs are illustrated <br />on Figure 2. Similar stormwater BMP management controls will be placed at the May Day No. <br />2 bench where excavated material will be stockpiled (Figure 3). Wildcat will then relocate the <br />north zircon storage unit to the south of the Genset zircon in order to provide access for <br />excavating and earth moving equipment. <br />2 Mr. Rauber has over 30 years of experience in geotechnical and environmental engineering much of which has be <br />spent in determining the cause and repairing or mitigating the effects of landslides. He is a licensed professional <br />engineer in Colorado, and licenses civil engineer and geotechnical engineer in California. He has repaired mitigated <br />landslides on Colorado's western slope, including at the West Elk Mine and Oxbow Mine site. Last year, Mr. <br />Rauber led a team that evaluated the cause and developed and implemented the successful repair to a major <br />landslide threatening a casino in Northern California. <br />EnviroGroup Limited <br />DEN 97, 749, 013v3 2 -29 -12 <br />4 <br />